1. Field of the Invention
The present invention relates to an omnidirectional or around-receiving antenna which has been primarily intended for receiving TV signals and has substantially circular antenna elements preferably tuned for different TV frequency ranges, connected to a joint amplifier, and cast within a common casing.
2. Description of the Prior Art
An antenna of this type is known previously from the Swedish Pat. No. 366,158, for example. In this patent the object is to provide a pleasant-looking antenna which is capable of receiving signals from substantially all directions. Its parts operating within different frequency ranges are circular, open dipoles made of a tube material and always tuned to the average frequency of each frequency range. The circular dipoles have been cast concentrically and spaced apart from each other inside a protective hood by using some foam plastic. The plastic material prevents mutual movement and vibration of the parts. In addition, the dipoles are connected, via symmetrically elements and tuned filters, to a joint wide-band amplifier.
It has been observed that, even though the receiving properties of this prior known antenna are nearly independent of the direction, a weak or "dead" point is formed in its receiving pattern in the direction of the open end of the dipole.